This invention relates to the manufacture of resilient workpieces. The invention is particularly applicable to the manufacture of liquid flow control valves, such as bite valves employed in liquid delivery devices for delivering water or other liquids to the mouth of an individuals, for example, cyclists.
The above-identified co-pending applications of which this application is a continuation-in-part disclose apparatus for positioning in the mouth of an individual, such as a cyclist, for selectively delivering liquid from a liquid source for consumption by the individual. These devices are in the nature of bite valves incorporating a deformable closure having one or more slits formed therein which are opened upon application of opposed external forces on the apparatus. The slit or slits will automatically close after termination of application of external forces.
The present invention encompasses both an apparatus and a method for cutting a workpiece having opposed first and second sides and formed from resilient material to create at least one cut in the workpiece extending between the first and second sides. The apparatus and method of the invention, as disclosed herein, have particular application to the manufacture of bite valves of the type referenced above. Utilizing the teachings of the present invention, one or more openings in the form of slits are formed in the resilient diaphragm of the bite valve while the diaphragm is in stretched condition. When practicing the teachings of the present invention a bite valve is manufactured which operates reliably to effectively seal off fluid flow through the bite valve when opposed bite forces are not applied thereto. The principles of the present invention are applicable to workpieces other than bite valves, for example other types of fluid flow control valves.
A workpiece constructed with the method and apparatus of this invention need not have any specific configuration to work properly. Thus, the workpiece need not be aligned in any particular manner with the cutter blade employed in the method. With this method, the section of the workpiece that is cut will be predisposed to seal. If, however, the current method is employed to cut a workpiece with a special sealing structure, the resilient slit will have enhanced sealing ability over a workpiece that is cut in a non-stretched manner.
The apparatus of the present invention includes first workpiece engagement means for engaging the first side of a workpiece. A second workpiece engagement means is provided for engaging the second side of the workpiece while the first side is engaged by the first workpiece engagement means. The second workpiece engagement means is cooperable with the first workpiece engagement means during relative movement between the first workpiece engagement means and the second workpiece engagement means to stretch the workpiece.
The apparatus also incorporates cutting means movable relative to the workpiece to cut the workpiece and form at least one cut in the workpiece extending between the first and second sides of the workpiece after the workpiece has been stretched by the first workpiece engagement means and the second workpiece engagement means and while the workpiece is in stretched condition.
The first workpiece engagement means and the second workpiece engagement means have opposed clamping surfaces for clampingly engaging the workpiece to maintain the workpiece in stretched condition while the cut is formed in the workpiece by the cutting means.
The invention also encompasses a method of cutting a workpiece having opposed first and second sides and formed from resilient material to create at least one cut in the workpiece extending between the first and second sides.
The method comprises the steps of stretching the workpiece and maintaining the workpiece in stretched condition.
While maintaining the workpiece in stretched condition, the stretched workpiece is cut to form at least one cut in the stretched workpiece extending between the first and second sides of the workpiece.
After the cutting step, the workpiece is allowed to return to an essentially unstretched condition.
The step of maintaining the workpiece in stretched condition comprises applying opposed clamping forces to the workpiece, one of the clamping forces being applied to the first side of the workpiece and the other of the clamping forces being applied to the second side of the workpiece.
Other features, advantages, and objects of the present invention will become apparent with reference to the following description and accompanying drawings.